I visited Diadora with my family. It is a good family hotel, adjusted to kids’ needs. However, I think that it is too expensive for the services it offers.
The price for 1 nigth (full board) for a family of 4 (kids are 5 and 10) is just over €200, which is pretty high. It has 4+ stars, so it should be really amazing. But I think there is a lot of room for improvement. The indoor pool is quite cold and small. The food in the restaurant is fine, but it should be even better. The service (hotel employees) is fine. The cleanliness is ok, but some parts of the room are ready to be refurbished.
All in all, if you get some kind of a discount, than it is well worth your stay.

Real kids hotel, so great for your children, but very crowded at breakfast and dinner time. Many pools and good quality. Comfortable rooms (family suite). Beach in front of hotel with plenty of sunloungers. Good alternative restaurants to the buffet. Buffet is very chaotic and more factory than restaurant. Don’t book sea side rooms, the hotel is not directly on the sea, there are apartments blocking the view. If your kids are very young (too young for the kids club) like ours, you may also consider booking the Iadera hotel of the same chain and 100 m further. More sophisticated, but perhaps less comfortable rooms for families.